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2010年  第31卷  第2期

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论文
Lung cancer is a leading cause of cancer death worldwide. Some lung cancer patients correlate with a gas of radon besides smoking. To search for common chromosomal aberrations in lung cancer cell lines established from patients induced by different factors, a combined approach of chromosome sorting, forward and reverse chromosome painting was used to characterize karyotypes of two lung adenocarcinoma cell lines: A549 and GLC-82 with the latter line derived from a patient who has suffered long-term exposure to environmental radon gas pollution. The chromosome painting results revealed that complex chromosomal rearrangements occurred in these two lung adenocarcinoma cell lines. Thirteen and twenty-four abnormal chromosomes were identified in A549 and GLC-82 cell lines, respectively. Almost half of abnormal chromosomes in these two cell lines were formed by non-reciprocal translocations, the others were derived from deletions and duplication/or amplification in some chromosomal regions. Furthermore, two apparently common breakpoints, HSA8q24 and 12q14 were found in these two lung cancer cell lines.
The whole mitochondrial genome sequence of red fox (Vuples vuples) was determined. It had a total length of 16 723 bp. As in most mammal mitochondrial genome, it contained 13 protein coding genes, two ribosome RNA genes, 22 transfer RNA genes and one control region. The base composition was 31.3% A, 26.1% C, 14.8% G and 27.8% T, respectively. The codon usage of red fox, arctic fox, gray wolf, domestic dog and coyote followed the same pattern except for an unusual ATT start codon, which initiates the NADH dehydrogenase subunit 3 gene in the red fox. A long tandem repeat rich in AC was found between conserved sequence block 1 and 2 in the control region. In order to confirm the phylogenetic relationships of red fox to other canids, phylogenetic trees were reconstructed by neighbor-joining and maximum parsimony methods using 12 concatenated heavy-strand protein-coding genes. The result indicated that arctic fox was the sister group of red fox and they both belong to the red fox-like clade in family Canidae, while gray wolf, domestic dog and coyote belong to wolf-like clade. The result was in accordance with existing phylogenetic results.
Microsatellites have been widely used in studies on population genetics, ecology and evolutionary biology. However, microsatellites are not always available for the species to be studied and their isolation could be time-consuming. In order to save time and effort researchers often rely on cross-species amplification. We revealed a new problem of microsatellite cross-species amplification in addition to size homoplasy by analyzing the sequences of electromorphs from seven catfish species belonging to three different families (Clariidae, Heteropneustidae and Pimelodidae). A total of 50 different electromorphs were amplified from the seven catfish species by using primers for 4 microsatellite loci isolated from the species Clarias batrachus. Two hundred and forty PCR-products representing all 50 electromorphs were sequenced and analyzed. Primers for two loci amplified specific products from orthologous loci in all species tested, whereas primers for the other two loci produced specific and polymorphic bands from some non-orthologous loci, even in closely related non-source species. Size homoplasy within the source species was not obvious, whereas extensive size homoplasy across species were detected at three loci, but not at the fourth one. These data suggest that amplification of products from non-orthologous loci and appearance of size homoplasy by cross-amplification are locus dependent, and do not reflect phylogenetic relationship. Amplification of non-orthologous loci and appearance of size homoplasy will lead to obvious complications in phylogenetic interference, population genetic and evolutionary studies. Therefore, we propose that sequence analysis of cross-amplification products should be conducted prior to application of cross-species amplification of microsatellites.
At present,transcription analysis of gene expression commonly uses housekeeping genes as control for normalization.In this study, the expression levels of three housekeeping genes including GAPDH, β-actin, and 18S rRNA in six tissues and five developmental stages of the Mandarin fish Siniperca chuatsi were assayed with quantitative real-time PCR (qPCR).Differences in expression levels were analyzed using geNorm program. The results demonstrate that β-actin is the most stable gene at developmental stages and GAPDH is the most stable in different tissues. While 18S rRNA expression during development is differentially regulated, which indicates it is suitable as an internal control for gene expression normalization at the developmental level. Overall, the data suggest that the two most stable housekeeping genes are enough to accurately calibrate gene expression in S. chuatsi. The significance of this study provided convincing references and methodology for housekeeping gene selection and normalization in gene expression analysis with regular PCR or qPCR.
The NEW GIFT Nile tilapia (Oreochromis niloticus niloticus L.) is a nationally certificated new strain selected over 14 years and 9 generations from the base strain of GIFT Nile tilapia, introduced in 1994. This new variety has been extended in most of areas of China. The management of genetically improved strains, including the genetic markers for identification is needed urgently. RAPD analysis was conducted and their conversion to SCAR markers was developed. From NEW GIFT Nile tilapia, two strain-specific RAPD bands, S304624 bp and S36568 bp were identified. The strain-specific RAPD bands were gel-purified, cloned, and sequenced. Locus-specific primers were then designed to amplify the strain-specific bands. PCR amplification was conducted to test the variations in allele frequencies of two converted SCAR markers among the NEW GIFT Nile tilapia and its base strains, as well as 7 additional farmed strains worldwide. The frequency of SCAR marker I (553 bp) was 85.7% in NEW GIFT Nile tilapia, but 16.7% in the base strain. The frequency of SCAR marker II (558 bp) was 91.4% in NEW GIFT Nile tilapia, but 0% − 70% in the 7 other strains. In order to confirm the utility of these two markers, an examination was conducted for a wild population from Egypt, resulted the frequency of SCAR I and II was 10% and 70%, respectively, much lower than that of New GIFT strain. The increase in allele frequency of these two SCAR markers suggests that these markers might be genetically linked to the quantitative trait loci (QTL) underlining the performance traits by long term selection, and indicate the bright potential of SCAR marker technology for tracking generations during selection progress and for distinguishing among genetically improved strain and other strains.
Psychological studies on human subjects show that contrast detection learning promote learner’s sensitivity to visual stimulus contrast. The underlying neural mechanisms remain unknown. In this study, three cats (Felis catus) were trained to perform monocularly a contrast detection task by two-alternative forced choice method. The perceptual ability of each cat improved remarkably with learning as indicated by a significantly increased contrast sensitivity to visual stimuli. The learning effect displayed an evident specificity to the eye employed for learning but could partially transfer to the naïve eye, prompting the possibility that contrast detection learning might cause neural plasticity before and after the information from both eyes are merged in the visual pathway. Further, the contrast sensitivity improvement was evident basically around the spatial frequency (SF) used for learning, which suggested that contrast detection learning effect showed, to some extent, a SF specificity. This study indicates that cat exhibits a property of contrast detection learning similar to human subjects and can be used as an animal model for subsequent investigations on the neural correlates that mediate learning-induced contrast sensitivity improvement in humans.
In order to study the relationship between landmarks and spatial memory in short-nosed fruit bat, Cynopterus sphinx (Megachiroptera, Pteropodidae), we simulated a foraging environment in the laboratory. Different landmarks were placed to gauge the spatial memory of C. sphinx. We changed the number of landmarks every day with 0 landmarks again on the fifth day (from 0, 2, 4, 8 to 0). Individuals from the control group were exposed to the identical artificial foraging environment, but without landmarks. The results indicated that there was significant correlation between the time of the first foraging and the experimental days in both groups (Pearson Correlation: experimental group: r=-0.593, P<0.01; control group: r=-0.581, P<0.01). There was no significant correlation between the success rates of foraging and the experimental days in experimental groups (Pearson Correlation: r=0.177, P>0.05), but there was significant correlation between the success rates of foraging and the experimental days in the control groups (Pearson Correlation: r=0.445, P<0.05). There was no significant difference for the first foraging time between experimental and control groups (GLM: F0.05,1=4.703, P>0.05); also, there was no significant difference in success rates of foraging between these two groups (GLM: F0.05,1=0.849, P>0.05). The results of our experiment suggest that spatial memory in C. sphinx was formed gradually and that the placed landmarks appeared to have no discernable effects on the memory of the foraging space.
The study analyzed 30 exterior meristic characters for 255 silver and bighead carp samples of 1- to 5-year-old collected from the National Primary Breeding Farm at Laojianghe Lake at the Middle Reach of the Yangtze River. Multivariate analysis was performed. In silver carp, the Euclidean distance was the greatest between the 1-year-old group and other age groups. Silver carp individuals were correctly classified at 98.0% accuracy with a discriminant function established by discriminant analysis based on meristic measurements. Similarly, bighead carp had the greatest distance between 1- to 2-year-old group and other age groups. Individuals of bighead carp were correctly classified at 90.7% accuracy by the discrimination function. The data showed that morphological transformation occurred during the life history of silver and bighead carp development. Eighteen meristic measurements showed highly significant differences, while four showed a significant difference between the two silver carp groups. Ten parameters decreased, while twelve measurements increased during development. In bighead carp, fourteen parameters were significantly different, while three parameters were significantly different between the two groups. Twelve parameters were significantly decreased and another five were increased during development. The results suggest allometric growth should be taken into account when identifying species, analyzing population differences and establishing germplasm standards based on morphology.
Habitat utilization and feeding biology of Himalayan Grey Langur (Semnopithecus entellus ajex) were studied from April, 2006 to April, 2007 in Machiara National Park, Azad Kashmir (Pakistan). The results showed that in the winter season the most preferred habitat of the langurs was the moist temperate coniferous forests interspersed with deciduous trees, while in the summer season they preferred to migrate into the subalpine scrub forests at higher altitudes. Langurs were folivorous in feeding habit, recorded as consuming more than 49 plant species (27 in summer and 22 in winter) in the study area. The mature leaves (36.12%) were preferred over the young leaves (27.27%) while other food components comprised of fruits (17.00%), roots (9.45%), barks (6.69%), flowers (2.19%) and stems (1.28%) of various plant species.
Reeves’s Pheasant (Syrmaticus reevesii) is a threatened pheasant species endemic to China. The habitat use of territorial male birds was surveyed by the help of live decoys in a core area of Dongzhai National Nature Reserve. The breeding habitat selection of this pheasant was examined at two scales (115 m and 250 m scale, i.e. 4.15 hm2 and 19.63 hm2, respectively), including the characteristics at distance scale. Investigation was based on line transect, RS and GIS in Dongzhai National Natural Reserve from 2001 to 2003. Moreover, a range of habitat variables were compared between used and control points at each scale, and stepwise logistic regression was applied to select the key scale and the key habitat factors in relation to breeding habitat selection of this bird. Our results stated that the territorial males at Baiyun occurred mostly in mixed forests, followed by fir forests, pine forests, shrubs, and broadleaf forests. The area of conifer forests was the key factor influencing habitat selection of this bird in breeding period at the scales of 115 m and 250 m, and the proximity of farmland was important for habitat selection in breeding seasons. Furthermore, Reeves’s Pheasants attached great importance to the scale of 115m. When considering a range of habitat variables at all scales within a multivariate regression, the leading factors having effect on habitat selection in the breeding period were areas of conifer forests at 115 m scale and the distance to farmland. In addition, these above results suggested that strengthening the management of suitable habitat, and optimizing the habitat configuration are important in promoting conservation of this bird. However, it also highlighted the importance of initiating future researches on the conifer forests and their impact on the population of Reeves’s Pheasants, which would be beneficial to promote the habitat conservation of this pheasant more effectively.
研究论文
Male allocare among nonhuman primates has frequently been investigated from the perspective of the caretaker. Here we examined whether male allocare relates to environmental factors or the females’ energetic stress. We researched the possible differences of allocare between sexes in free-ranging black-and-white snub-nosed monkeys (Rhinopithecus bieti) in Tibet. A combination of stepwise least squares regression analysis was used to identify the influence of ecological factors (temperature, rainfall, etc.) and infant age that best account for seasonal variation of allocare. The results indicate, except for the functions of infant age, however, that male allocare is a negative function of temperature and female allocare is a positive function of temperature. Specifically, we tested the energetic stress hypothesis, which predicts that the energetic burden of females in a severe environment favour an increased rate of male allocare during the seasons of high energetic stress. We analyzed the allocare difference between high energetic stress season (Mar -Apr), when temperature was low, food availability was scarce, and infants were young, and low energetic stress season (Jun -Aug), based on data obtained during June 2003 − June 2004. Our results supported the energetic stress hypothesis because male allocare in high energetic stress season was higher than that of in low energetic stress season and female allocare was reverse. Therefore, we propose it is the energetic stress on female that make male allocare possible. Male take these interests for other aims and meet some functional hypothesis, which are addressed from the perspective of the male.